The present invention relates to a method and an apparatus for transporting flat, generally rectangular objects, such as printed products, arriving in an overlapping formation.
A method and an apparatus of this type are disclosed, for example, in WO99/55609. The flat objects, such as printed products, are transported in an overlapping stream resting on a belt conveyor. In this case, the objects can have a different extent, as viewed in the conveying direction, or can be arranged in the overlapping formation with a different overlap distancexe2x80x94that is to say the distance between the leading edges of successive objects. Connected downstream of the belt conveyor is a clamp transporter, which in each case grips one sectionxe2x80x94that is to say a specific number of objectsxe2x80x94by means of a single transport clamp in order to be transported onward. In order that one tongue of the transport clamp can in each case engage between the last object of the preceding section and the first object of the section to be gripped, a possibility of engagement is created in the overlapping stream. This limits the processing speed and requires complicated apparatus.
It is therefore an object of the present invention to provide a method and an apparatus for transporting flat, at least approximately rectangular objects arriving in an overlapping formation which, with a high processing capacity and using simple apparatus, permits the transport of objects which have a specific first extent in one direction and a variable second extent in a direction running at right angles thereto.
The above and other objects and advantages of the present invention are achieved by the provision of a method and apparatus which includes a conveying conveyor which conveys the objects in an overlapping stream in which the overlap distance is constant, irrespective of the extent of the objects. In addition, the objects in the overlapping stream are arranged with a specific first extentxe2x80x94that is to say always the same extentxe2x80x94running in the conveying direction. Their second extent, at right angles to the conveying direction, can be variable. In other words, in spite of different formats, the objects are conveyed in a regular overlapping stream with a constant overlap distance and constant length of the mutual overlap of two adjacent objects in each case. This permits transport clamps to be arranged at a fixed distance one behind another, irrespective of the format of the objects, in order in each case to grip a specific number of objectsxe2x80x94a so-called sectionxe2x80x94by means of a single transport clamp, each object being held by a single transport clamp in order to be transported onward. At the same time, the transport clamps can grip the objects conveyed in the overlapping stream to transport them onward without the formation of gaps.
In one preferred embodiment, the apparatus further includes an upstream feed conveyor which is configured to convey the objects in an overlapping stream with the first extent running at right angles to its conveying direction. A transfer device is positioned between the feed conveyor and the conveying conveyor for transferring objects from the feed conveyor into the overlapping stream on the conveying conveyor.